Marta Orselli

The SU(2) x SU(2) sector in the string dual of N=6 superconformal Chern-Simons theory

We examine the string dual of the recently constructed N=6 superconformal Chern–Simons theory of Aharony, Bergman, Jafferis and Maldacena (ABJM theory). We focus in particular on the SU(2)×SU(2) sector. We find a sigma-model limit in which the resulting sigma-model is two Landau–Lifshitz models added together. We consider a Penrose limit for which we can approach the SU(2)×SU(2) sector. Finally, we find a new Giant Magnon solution in the SU(2)×SU(2) sector corresponding to one magnon in each SU(2). We put these results together to find the full magnon dispersion relation and we compare this to recently found results for ABJM theory at weak coupling.

Finite size Giant Magnons in the string dual of N=6 superconformal Chern-Simons theory

We find the exact solution for a finite size Giant Magnon in the SU(2) × SU(2) sector of the string dual of the = 6 superconformal Chern-Simons theory recently constructed by Aharony, Bergman, Jafferis and Maldacena. The finite size Giant Magnon solution consists of two magnons, one in each SU(2). In the infinite size limit this solution corresponds to the Giant Magnon solution of arXiv:0806.4959. The magnon dispersion relation exhibits finite-size exponential corrections with respect to the infinite size limit solution.

Heating up the BIon

We propose a new method to consider D-brane probes in thermal backgrounds. The method builds on the recently developed blackfold approach to higher-dimensional black holes. While D-brane probes in zero-temperature backgrounds are well-described by the Dirac-Born-Infeld (DBI) action, this method addresses how to probe thermal backgrounds. A particularly important feature is that the probe is in thermal equilibrium with the background. We apply our new method to study the thermal generalization of the BIon solution of the DBI action. The BIon solution is a configuration in flat space of a D-brane and a parallel anti-D-brane connected by a wormhole with F-string charge. In our thermal generalization, we put this configuration in hot flat space. We find that the finite temperature system behaves qualitatively different than its zero-temperature counterpart. In particular, for a given separation between the D-brane and anti-D-brane, while at zero temperature there are two phases, at finite temperature there are either one or three phases available.

Non-planar ABJM theory and integrability

Using an effective vertex method we explicitly derive the two-loop dilatation generator of ABJM theory in its SU(2) × SU(2) sector, including all non-planar corrections. Subsequently, we apply this generator to a series of finite length operators as well as to two different types of BMN operators. As in = 4 SYM, at the planar level the finite length operators are found to exhibit a degeneracy between certain pairs of operators with opposite parity — a degeneracy which can be attributed to the existence of an extra conserved charge and thus to the integrability of the planar theory. When non-planar corrections are taken into account the degeneracies between parity pairs disappear hinting the absence of higher conserved charges. The analysis of the BMN operators resembles that of = 4 SYM. Additional non-planar terms appear for BMN operators of finite length but once the strict BMN limit is taken these terms disappear.

Thermodynamics of the hot BIon

Abstract We investigate the thermodynamics of the recently obtained finite temperature BIon solution of [G. Grignani, T. Harmark, A. Marini, N.A. Obers, M. Orselli, Heating up the BIon, arXiv:1012.1494 [hep-th] ], focusing on two aspects. The first concerns comparison of the free energy of the three available phases for the finite-temperature brane–antibrane–wormhole configuration. Based on this we propose a heuristic picture for the dynamics of the phases that involves a critical temperature below which a stable phase exists. This stable phase is the finite temperature analogue of the thin throat branch of the extremal brane–antibrane–wormhole configuration. The second aspect that we consider is the possibility of constructing a finite temperature generalization of the infinite spike configuration of the extremal BIon. To this end we identify a correspondence point at the end of the throat where the thermodynamics of the D3–F1 blackfold configuration can be matched to that of k non-extremal black fundamental strings.

Quantum mechanical sectors in thermal N=4 super-Yang–Mills on R×S3

Abstract We study the thermodynamics of U ( N ) N = 4 super-Yang–Mills (SYM) on R × S 3 with non-zero chemical potentials for the SU ( 4 ) R-symmetry. We find that when we are near a point with zero temperature and critical chemical potential, N = 4 SYM on R × S 3 reduces to a quantum mechanical theory. We identify three such critical regions giving rise to three different quantum mechanical theories. Two of them have a Hilbert space given by the SU ( 2 ) and SU ( 2 | 3 ) sectors of N = 4 SYM of recent interest in the study of integrability, while the third one is the half-BPS sector dual to bubbling AdS geometries. In the planar limit the three quantum mechanical theories can be seen as spin chains. In particular, we identify a near-critical region in which N = 4 SYM on R × S 3 essentially reduces to the ferromagnetic X X X 1 / 2 Heisenberg spin chain. We find furthermore a limit in which this relation becomes exact.

Matching the Hagedorn temperature in AdS/CFT

We match the Hagedorn/deconfinement temperature of planar N=4 super Yang-Mills (SYM) on RxS{sup 3} to the Hagedorn temperature of string theory on AdS{sub 5}xS{sup 5}. The match is done in a near-critical region where both gauge theory and string theory are weakly coupled. The near-critical region is near a point with zero temperature and critical chemical potential. On the gauge-theory side we are taking a decoupling limit found in Ref. 7 in which the physics of planar N=4 SYM is given exactly by the ferromagnetic XXX{sub 1/2} Heisenberg spin chain. We find moreover a general relation between the Hagedorn/deconfinement temperature and the thermodynamics of the Heisenberg spin chain and we use this to compute it in two distinct regimes. On the string-theory side, we identify the dual limit for which the string tension and string coupling go to zero. This limit is taken of string theory on a maximally supersymmetric pp-wave background with a flat direction, obtained from a Penrose limit of AdS{sub 5}xS{sup 5}. We compute the Hagedorn temperature of the string theory and find agreement with the Hagedorn/deconfinement temperature computed on the gauge-theory side.

The superstring Hagedorn temperature in a pp-wave background

The thermodynamics of type-IIB superstring theory in the maximally supersymmetric plane wave background is studied. We compute the thermodynamic partition function for non-interacting strings exactly and the result differs slightly from previous computations. We clarify some of the issues related to the Hagedorn temperature in the limits of small and large constant RR 5-form. We study the thermodynamic behavior of strings in the case of AdS3 × S3 × T4 geometries in the presence of NS-NS and RR 3-form backgrounds. We also comment on the relationship of string thermodynamics and the thermodynamic behavior of the sector of Yang-Mills theory which is the holographic dual of the string theory.

Holographic 3-point function at one loop

A bstractWe explore the recent weak/strong coupling match of three-point functions in the AdS/CFT correspondence for two semi-classical operators and one light chiral primary operator found by Escobedo et al. This match is between the tree-level three-point function with the two semi-classical operators described by coherent states while on the string side the three-point function is found in the Frolov-Tseytlin limit. We compute the one-loop correction to the three-point function on the gauge theory side and compare this to the corresponding correction on the string theory side. We find that the corrections do not match.

Finite-size corrections for quantum strings on {\text{Ad}}{{\text{S}}_4} \times \mathbb{C}{P^3}

We revisit the calculation of curvature corrections to the pp-wave energy of type IIA string states on